This invention is directed to the field of wireless communications and in particular to network system for providing regional wireless communications.
The worldwide demand for increased connectivity, especially via wireless networks has increased dramatically in the last decade. Individual subscribers to a network have come to expect high quality, seamless, connectivity within the network and between the network and other networks. Additionally, connectivity demands by network subscribers, once confined almost exclusively to narrowband data such as voice services, now include voice, data, text, sound and video typically considered wideband data. Therefore, concomitant with the increased demand for connectivity has been an increase in demand for bandwidth both in terms of bandwidth allocated to the individual subscriber terminal within the network and in terms of the overall network bandwidth. The bandwidth demands are increasing dramatically in part due to the surge in Internet related services that are being provided via these networks.
To address the need for more bandwidth and better connectivity, a number of new technologies and systems, both hardware and software, are being developed, with steadily improving performance, to deliver voice, data, text, sound, and video at higher speeds and decreasing prices.
While much of the network connectivity has traditionally been supplied by so called wired networks, wireless networks are becoming a more and more important part of the overall approach to connectivity. Wireless systems for the delivery of network services include those based on transmission from and to terrestrial towers, transmission from and to satellites in orbit around the earth and, very recently, transmission to and from atmospheric platforms. Examples of terrestrial tower based wireless systems included cellular telephone systems and point-to-point microwave local loops. Satellite systems include low-earth orbit (LEO), medium-earth orbit (MEO), and geostationary earth orbit (GEO), systems. Transmission to and from an atmospheric platform for providing network connectivity is described in the co-pending applications referenced hereinabove.
As described in the co-pending applications, the atmospheric platform serves as a central node, providing connectivity between the various elements in a wireless communications network. Such an atmospheric platform based network configuration offers distinct benefits and advantages over both terrestrial tower and satellite systems. Some of the advantages are described below. One advantage is that the atmospheric platform provides a simple network topology. For example, the network has one node for all subscribers instead of many nodes as in a mesh topology typical of terrestrial tower based wireless systems. Moreover, the atmospheric platform offers a clear, unobstructed signal path to nearly every rooftop in the signal footprint of the network owing to its relatively high altitude compared to terrestrial towers. Further, the atmospheric platform based network provides for the use of smaller power-aperture products of both the subscriber terminals or user equipment units (UE) and platform antennas for achieving information rates greater than possible with systems such as those involving orbiting satellites. Additionally, the atmospheric platform based network can be routinely serviced, improved, and upgraded by modifying the equipment aboard the atmospheric platform, an action that is not routine with satellites. Services to all subscribers can be improved or enhanced by modifying a single node only, i.e., the atmospheric platform, rather than simultaneously upgrading tens to hundreds of towers of typical terrestrial wireless networks. Also, most components selected for the communications network equipment aboard the platform can be of a commercial grade from vendors in the terrestrial wireless communications markets, rather than of a space grade as required by satellites.
However, there are often severe practical limitations affecting weight, linear dimensions, power, and thermal performance imposed on the network equipment operating aboard the atmospheric platform. While they are limitations for operation on the airborne platform, the weight, linear dimensions, power and thermal performance are seldom bothersome to equipment installations on the ground. To accommodate the use aboard an airborne platform, it is often necessary to xe2x80x9crepackagexe2x80x9d equipment with attending added cost and technical risk. The task of xe2x80x9crepackagingxe2x80x9d may include, but is not limited to, reconfiguring circuit modules and boards, redesigning power conditioning circuits and their interfaces, introducing fluid cooling to components normally requiring air flow only, and manufacturing of special-purpose mechanical fixtures and interfaces. Often with components that need to be xe2x80x9crepackagedxe2x80x9d, a close working relationship with the vendor or vendors of the equipment is required in order to be successful. For highly complex equipment, such as state-of-the-industry packet switches, slight modifications can profoundly affect performance. In the highly competitive telecommunications markets, switch manufacturers optimize their products for their established customers to maintain their sales volumes and market share, and will pursue new applications requiring modifications of their core products typically only if stimulated by large funding and/or the prospect of a large future sales opportunity.
Consequently, when possible, it is advantageous to operate the network equipment in conditions as closely as possible to those specified by the vendor for normal operation, in order to preclude the need for repackaging. Operating network equipment under xe2x80x9cnormalxe2x80x9d conditions eliminates risk and reduces cost. Since the most complex equipment in any given network is that associated with network processing and switching, a great advantage can be realized by minimizing the need for repackaging. One way to overcome the need for repackaging in the case of the atmospheric platform based network is to locate the xe2x80x9cswitchxe2x80x9d on the ground rather than in the atmospheric platform. However, this solution is not without its problems. One problem to overcome is how to accomplish this without sacrificing network connectivity or other performance characteristics of the network.
It would be advantageous to have a wideband wireless communications system that combined the benefits of an airborne platform with the benefits of network processing and switching on the ground. Such a system could use standard equipment on the ground rather than specially designed equipment for the airborne platform.
The present invention is a novel communications network utilizing an airborne or atmospheric platform as a central node in a star topology wireless communication network serving a plurality of subscribers. Moreover the communications network of the present invention incorporates communications equipment aboard the airborne platform providing a bidirectional, aggregated wideband wireless communications channel called a trunkline between the airborne platform and one or more ground stations or gateways so that complex network equipment, for example switches and channelizers, can be located on the ground instead of on the airborne platform.
According to the present invention, a novel network architecture provides wireless communications, such as voice, data, images, video, and multi-media services, to a geographic area large enough to encompass a city and its neighboring communities. The network of the present invention can provide broadband and narrowband data services to subscribers by utilizing signal bandwidths at either microwave or millimeter wave (MMW) carrier frequencies for providing wireless subscriber links. The present invention utilizes a wide, contiguous or non-contiguous band of spectrum in point-to-point links serving as wireless trunklines connecting the network gateways or ground stations, on the ground, to the communications equipment aboard an airborne platform. Each trunkline carries the combined signal traffic from a multitude of subscribers on the ground to the communications switches at the network gateway/ground station, and vice versa, via the airborne platform. The use of wireless trunklines enables all types of switching, including circuit, cell, packet, or frame, or any combination thereof, to be performed by standard equipment housed in facilities on the ground rather than by specially designed equipment located on the airborne platform. The wireless trunklines have bandwidths wide enough to convey the aggregated data traffic from the entire set of active users of the network with an atmospheric platform as its central relay node.
In one aspect of the invention, a system for providing wireless communication services in a geographic area using a star network topology is provided. The system includes at least one atmospheric platform serving as a central relay or node for the geographic area. The atmospheric platform carries a payload that comprises communications equipment. The system further includes a plurality of user equipment units located within the geographic area and at least one ground station or gateway for providing an information pathway between the user equipment units. The gateway has network processing and switching equipment for routing the information between the users. The system still further includes a wireless trunkline for carrying signals between the gateway and the atmospheric platform. The wireless trunkline comprises an uplink portion and a downlink portion. The downlink portion carries aggregated information, which was transmitted from one or more of the user equipment units, from the platform to the gateway. The uplink portion carries the aggregated information, which is routed by the network switching equipment to one or more intended user equipment units, from the gateway to the platform. The gateway may further provide information pathways from the platform to user equipment units outside of the geographic area through existing communications infrastructure, such as public switched telephone network (PSTN), fiber optics, satellites or another atmospheric platforms servicing different geographical areas.
In another aspect of the present invention, an apparatus is provided that aggregates and transmits a plurality of signals and receives and de-aggregates the plurality of signals using a wireless trunkline. The wireless trunkline is between an atmospheric platform and a ground-based gateway. The atmospheric platform has an airborne antenna array subsystem and an airborne trunkline antenna subsystem on board. The gateway includes a gateway antenna subsystem and a gateway network processing subsystem, including a network switch. The apparatus of the invention comprises a downlink apparatus and an uplink apparatus.
The downlink apparatus comprises a payload portion on the atmospheric platform and a gateway portion on the gateway. The payload portion accepts a plurality of downlink signals from the airborne antenna array subsystem. The downlink signals are aggregated to create a downlink trunkline signal. Further the payload portion passes the downlink trunkline signal to the airborne trunkline antenna subsystem for transmission via the wireless trunkline to the gateway. The gateway portion accepts the downlink trunkline signal received from the wireless trunkline by way of the gateway antenna subsystem. The downlink trunkline signal is de-aggregated into the plurality of downlink signals by the gateway and passes the de-aggregated downlink signals to the gateway network processing subsystem for routing and transmission via the uplink apparatus.
The uplink apparatus likewise has a gateway portion on the gateway and a payload portion on the atmospheric platform. The gateway portion of the uplink apparatus accepts a plurality of uplink signals from the gateway network processing subsystem. The uplink gateway portion aggregates the uplink signals to create an uplink trunkline signal and passes the uplink trunkline signal to the gateway antenna subsystem for transmission by way of the wireless trunkline to the atmospheric platform. The payload portion accepts the uplink trunkline signal received from the wireless trunkline with the airborne trunkline antenna subsystem. The uplink trunkline signal is de-aggregated into the plurality of uplink signals. The de-aggregated uplink signals are passed to the airborne antenna array subsystem for transmission to the intended recipients.
The payload portion of the downlink apparatus comprises a plurality of sets of frequency conversion multiplexers, which aggregates and frequency shifts the received signals several times until the downlink trunkline signal is created. The gateway portion of the downlink apparatus comprises a plurality of sets of frequency conversion demultiplexers, which de-aggregates and frequency shifts the downlink trunkline signal several times until the uplink trunkline signal is created.
In still another aspect of the invention, a method of wireless communication is provided. The method uses the system and apparatus described above for receiving and transmitting signals between the user equipment units, the airborne platform and the gateway using a wireless trunkline. In one embodiment, the method also uses existing communications infrastructure to receive and transmit signals outside of the geographical area that the system serves.
The method of the present invention comprises, in the payload portion of the downlink, the step of aggregating a plurality of downlink signals that have been accepted or received from the airborne antenna array subsystem. The airborne antenna array subsystem receives signals from the user equipment units, for example. The downlink signals are aggregated to create a downlink trunkline signal. The method further comprises the step of passing the downlink trunkline signal to the airborne trunkline antenna subsystem for transmission via the wireless trunkline to the gateway.
In the gateway portion of the downlink, the method further comprises the step of de-aggregating the downlink trunkline signal that has been accepted or received from gateway antenna subsystem by way of the wireless trunkline. The downlink trunkline signal is de-aggregated into the plurality of downlink signals by the gateway. The method further comprises the step of passing the de-aggregated downlink signals to the gateway network processing subsystem for routing and transmission via the uplink apparatus.
In the gateway portion of the uplink apparatus, the method of the invention accepts the plurality of uplink signals from the gateway network processing subsystem. The method further comprises the step of aggregating the uplink signals to create an uplink trunkline signal. The uplink trunkline signal is passed to the gateway antenna subsystem for transmission by way of the wireless trunkline to the atmospheric platform.
In the payload portion of the uplink apparatus, the method of the invention further comprises the step of de-aggregating the uplink trunkline signal that has been accepted or received from the wireless trunkline using the airborne trunkline antenna subsystem. The uplink trunkline signal is de-aggregated into the plurality of uplink signals. The de-aggregated uplink signals are passed to the airborne antenna array subsystem for transmission to the intended recipients.
The present invention provides a robust system, apparatus and method that combines the benefits of providing the network switching capability on the ground with the benefits of using an airborne platform instead of costly satellite technology. The network of the present invention is particularly useful in broadband and narrowband communications markets, serving the needs of users requiring fixed, portable, and mobile communications services.